A method for performing 3D motion tracking of the shoulder joint with respect to the thorax, using MARG sensors and a data fusion algorithm, is proposed. Two tests were done: 1) qualitative and quantitative analysis of the response of the sensors, static position and during motion, with and without the proposed data fusion algorithm; 2) motion tracking of the shoulder joint with the upper arm, the thorax, and the shoulder joint respect to the thorax. Qualitative analysis of experimental results showed that despite slight variations regarding the evaluated motion, these variations did not have repercussions on the estimated orientation. Quantitative analysis showed that the estimated orientation did not exhibit significant variations, in five minutes, such as drift errors (about 0.1° in static position and less than 1.8° during motion), variations due to noise or magnetic disturbances (RMSE less than 0.04° static position and less than 1° during motion); no singularity problems were reported.

The main contributions of this research are a multisensor data fusion algorithm, which combines the complementary properties of gyroscopes, accelerometers, and magnetometers in order to estimate the 3D orientation of two body segments separately and with respect to another body segment considering the spatial relationship between them; and a method for performing 3D motion tracking of two body segments, based on the estimation of their orientation, including motion compensation. The proposed method is applicable to monitoring devices based on IMU/MARG sensors; the performance was evaluated using a customized motion analysis system.

提出了一种利用MARG传感器和数据融合算法对肩关节相对于胸部进行3D运动跟踪的方法。进行了两个测试：1）使用和不使用建议的数据融合算法，对传感器的响应，静态位置和运动过程进行定性和定量分析；2）上臂，胸廓以及肩关节相对于胸廓的肩关节运动跟踪。对实验结果的定性分析表明，尽管所评估的运动略有变化，但这些变化对估算的方向没有影响。定量分析表明，估计的方向在五分钟内没有显示出明显的变化，例如漂移误差（静态位置约为0.1°，运动时小于1.8°），由噪声或电磁干扰引起的变化（RMSE小于静态位置0.04°，运动时小于1°）；没有奇点问题的报道。

这项研究的主要贡献是一种多传感器数据融合算法，该算法结合了陀螺仪，加速度计和磁力计的互补特性，以便分别估计两个身体片段的3D方向，并考虑到它们之间的空间关系相对于另一个身体片段的3D方向。 ; 以及基于两个身体段的方向的估计（包括运动补偿）执行3D运动跟踪的方法。该方法适用于基于IMU / MARG传感器的监控设备。使用定制的运动分析系统评估性能。